well one thing you can do to slow them down is gently vacuum them off the plant (i did it when i first ran into the little buggers on my plant and it did a fantastic job of slowing them down) you can also raise the temps a bit in your grow area, higher temps slow them down.

As for exterminating them, the only thing i have experience with at the moment is a Bayer Crop science spray made to kill a variety of garden pests, and its slowing them down but it sure as hell isnt killing them all because i keep finding new leafs with spots ect ect. Most of the time i see people recommend neem oil, its organic and its supposed to work on them like evil juju (slow but powerful juju), ive personally ordered some because i wanna get these mites under control before i send my girl into flowering. I'll be sure to share my results with you if your still havin problems.